金矿尾矿废水及废渣浸出液的理化特征及生物毒性效应

Physical-Chemical Properties and Biological Toxic Effect of Wastewater and Sludge Leachate in Gold Mine Tailing

为了研究金矿矿区农田周边堆存的废渣浸出液及矿区农田灌溉用水的理化特征及生物毒性效应,通过对黔西南"水银洞"金矿进行现场调查并对农田周边大量堆放的矿区基岩、尾矿废渣、尾矿区库底泥及进入农田灌溉水渠的尾矿库废水、外排废水等样品及金矿上游地表水进行全面采集和理化分析,并进行发光细菌急性生物毒性测定。结果表明:所有矿区样品浸出液及水体中的Cd均超出地表水质量Ⅲ类限值和农田灌溉水质标准,矿区上游地表水和下游废水中CN-含量超出地表水质量Ⅲ类限值。生物毒性数据表明,上述样品浸出液及水体的生物毒性从高至低为:下游外排废水>尾矿库废水>底泥浸出液>尾矿废渣浸出液>矿区基岩浸出液>矿区上游地表水。说明,该金矿开采过程中大量产生和堆放的基岩、尾矿废渣、尾矿库底泥被地表水和雨水淋溶或浸泡后其浸出液将对周边农田土壤产生危害;进入农田灌溉水渠的尾矿库废水、外排废水具有较强的生物毒性,其排放会给下游的农业生态环境和水生生态环境及人畜健康造成一定危害,金矿带来的环境污染应引起重视。

Onsite investigation was undertaken for Shuiyindong gold mine in Southwest of Guizhou,samples of bedrocks piled surround farmland,sludge and sediment in mine tailing,wastewater for irrigation,wastewater discharged,and surface water in upstream of mine were comprehensively collected and analyzed,acute toxicity of luminescent bacteria were also determined to study the physical-chemical properties and biological toxic effects of wastewater and sludge leachate in the gold mine tailing.The results showed that all the Cd in all leachate and wastewater exceeded the quality standard III category of surface water and irrigation water quality standard,CN-concentration in downstream wastewater was also exceeded the standard.The toxicity of leachate and water tested above were： downstream wastewater discharged tailing wastewater sediment leachate tailing sludge leachate mine bedrock leachate upstream surface water.It indicated that the leachate of large number of bedrock produced,tailing sludge,tailing sediment could be harmful to surrounding soil after eluviated by surface water and rainfall.Wastewater going to irrigation and wastewater discharged had high biological toxicity,their discharge will also bring harzard to agro ecosystem,aquatic ecosystem,and human and animals＇ health downstream,therefore,the environmental pollution from gold mining should be more strengthened.